I just looked up the BHK 300s (I wasn’t familiar with them). It seems they will work fine with Sound Labs from a power perspective: 300W into 8 Ohms, 1000W into 2 Ohms. The fact that their output increases with decreasing impedance suggests they have FET output transistors and that the tube is for an earlier stage of amplification.
If you’re obsessive (like many of us are in this affliction, er hobby) you might want to contact PS Audio and ask how their amps handle ~1 Ohm impedance, as the Sound Labs’ impedance dips quite low (down to 1.2 Ohm if memory serves) above 10kHz. The good news is that there is not a huge need for power at higher frequencies. You also might want to ask what happens with the amps at high impedance–again SLs have pretty nonlinear impedance, and as I recall they climb to ~40 Ohm below 50 Hz, which is why tube amps, especially OTLs like AtmaSphere, are a good match.
Again, I’m pretty confident the BHKs will be fine, but if you want to obsess…
Best of luck!
